Premium Bonds Odds Calculator
See the expected annual winnings on your Premium Bonds holding, an honest median (typical) outcome, your monthly odds of winning anything at all, and how it stacks up against an ordinary savings account.
Estimate only. Estimates only, based on the prize rate and odds you enter — not financial advice. Premium Bonds are provided by NS&I; verify current rates, odds and limits at nsandi.com before making a decision.
≈ £32 a month, on average
Half of holders like you would expect to win more than this over a year, and half less — because a small number of very large prizes pull the average upward.
Based on your holding and the published per-Bond odds — this is exact, not an estimate.
Vs. a 4.3% savings account
⚠ Illustrative easy-access rate — check current best-buy rates.
- Savings interest (gross)
- £430
- Savings interest, net of tax (basic-rate, PSA used elsewhere)
- £344
- Premium Bonds advantage vs. basic-rate net
- £36
- Savings interest, net of tax (higher-rate, PSA used elsewhere)
- £258
- Premium Bonds advantage vs. higher-rate net
- £122
Premium Bonds come out ahead
Premium Bonds come out ahead
Who Premium Bonds suit
- Higher and additional-rate taxpayers who've already used their Personal Savings Allowance elsewhere — every pound you win is completely tax-free, which a taxable savings account can't match.
- People with larger holdings, where results track the advertised prize rate much more reliably month to month.
- Anyone who likes the lottery-style excitement and can treat the money as "maybe I'll win, maybe I won't" rather than counting on a guaranteed return.
- If you need predictable, guaranteed growth — for a house deposit deadline, for example — an easy-access or fixed savings account is the safer choice.
Things worth knowing
- Every Premium Bonds prize, from £25 to £1 million, is completely tax-free and doesn't use up your Personal Savings Allowance.
- Unlike interest, winnings aren't guaranteed each month — you could win nothing for months and then win big, or vice versa.
- The bigger your holding, the more reliably your actual winnings track the advertised prize rate — small holdings see much more random swings.
- NS&I holds unclaimed prizes indefinitely — use their prize checker regularly, especially if you've moved house.
This is an illustrative model of an independent-draw prize system, not a guarantee of any individual result. Your actual winnings in any given month or year may be higher or lower than shown here.
How this is worked out
NS&I Premium Bonds pay no interest. Instead, the whole "prize fund rate" is distributed as tax-free prizes in a monthly draw, and every eligible £1 Bond number has the same published odds of winning. The "expected annual winnings" figure above is simply your holding multiplied by the prize fund rate — the same maths as ordinary interest, and the number NS&I itself quotes. But it's a statistical average across millions of Bond numbers, not what a typical holder actually experiences: a small number of huge prizes (including the monthly £1 million jackpots) pull the average upward, so the typical (median) holder tends to win somewhat less than the average in any given year. We show an approximate median — roughly 85% of the mean for a mid-size holding — alongside the mean so you can see both sides of the picture. We also calculate the exact probability of winning at least one prize this month, using the standard "independent draws" model: with n Bond numbers each having a 1-in-N chance, the probability of winning nothing is (1 − 1/N)^n, so the probability of winning something is 1 minus that. Larger holdings have many more Bond numbers in the draw, so their results track the advertised rate far more reliably than a small holding's.